import cv2
import numpy as np
image=cv2.imread('figure.png')
cv2.imshow('BGR',image)
b,g,r=cv2.split(image)
cv2.imshow('B',b)
imgZeros=np.zeros_like(image)
imgZeros[:,:,0]=b
cv2.imshow('channel B',imgZeros)
cv2.waitKey()
cv2.destroyAllWindows()